Patterned nanoporous-gold thin layers: Structure control and tailoring of plasmonic properties

Nanoporous gold (NPG) layers have been fabricated by silver leaching of Ag–Au alloys with different dealloying processes and working temperatures. Structural, compositional and optical properties of the different samples have been analyzed with several experimental techniques: scanning and transmission electron microscopy (SEM/TEM), electrochemical impedance spectroscopy (EIS), Rutherford back scattering (RBS), spectroscopic ellipsometry. A periodic pattern has been realized on samples surface with focused ion beam (FIB) lithography in order to exploit NPG metallic behavior for surface plasmon polaritons (SPPs) excitation. The plasmonic response of the several NPG gratings has been analyzed and related to structural properties and fabrication conditions.

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► Dealloying of Ag–Au alloy films was performed at different working temperatures.
► Nanoporous gold films were optically/physically characterized with several techniques.
► Nanoporous gold surfaces have been patterned with focused ion beam lithography.
► The plasmonic response of different samples has been analyzed.
► Plasmonic and optical response has been related to the porous structure.